Wellllllllllllll,

In domestic frig's, fractionalization doesn't seem to be too big of a problem, unless it's very severe.

ICOR recommends that you recover and recharge with new refrigerant if fractionalization occurs. But really now, how can you tell on somebody's frig if it happens??

From what I understand, the R22 component of HotShot is what is lost first. I know a few that simply pull down the system, fix the leak, put it back in, add more refrigerant, and 'ship-it' without any problems.

About mineral oil and 134a....

I went to a site listed from one of the super-fixers (Prof Sporlan maybe???) and saw a cap tube bleed off from the high side to the low. Perhaps 134a could be used in such a system with mineral oil provided an oil seperator and oil return line could be utilized, especially on a long vertical run. Then oil return would not be a problem?